This invention relates to a drinking water supplying apparatus and particularly to a drinking water supplying apparatus including a water heating tank which sends out the water by the force of the vapor pressure of the boiling water so that only the boiled water can flow out of the apparatus.
Drinking water supplying apparatus typically include a water heating pipe through which the cold water flows and is heated by a heating coil provided around the heating pipe. Since the temperature and the flow rate of the ingoing water can not be always kept constant, and the scale formed inside the pipe affects the heat transfer into the pipe in some degree, such apparatus cannot provide actually boiled water when a large quantity of drinking water is taken out from the apparatus. Moreover, in order to boil the water flowing in the pipe, it is necessary to increase the length of the heating coil as well as the heating pipe since the heat conducting effect of the pipe is limited and the flowing water can only receive part of the heat from the heating coil. This increases the power consumption.
There is also another type of drinking water supplying apparatus which includes a filter to clean the water. However, if replacement of the filter is neglected, the filter may become an ideal enviroment for breeding bacteria.